Primary and metastatic human tumor tissues are being studied comparatively to determine if differences can be identified possibly denoting a shift in cell populations in metastatic tumor. In addition, normal tissue samples and serum are being collected as required. The patients have been clinically followed in order to be able to relate any of these parameters with clinical course. To date, a computerized software system has been developed which allows a monthly printout of patient disease status and survival. Input of our population is current to date. The most interesting laboratory development thus far is the finding of a reduction in tumor plasminogen activator released into media from cultured metastatic cells versus cultured primary. A number of patients have been studied to date and this appears to be a true finding. There are also some possible chromosome abnormalities seen on banding which may prove to be of significance. Progress continues, and we are trying to add additional laboratory groups and clinical resources to our program.